Theoretical studies of the structure of C2H2 adsorbed on Si(0Â 0Â 1)

► The MSC calculation shows there is only one possible structure model when C2H2 adsorbed on Si(0 0 1)-(2 × 1) surface. ► The calculated curves of the coexistence of the dimerized structure and the rotational one are in good agreement with the experimental data, not the coexistence of the dimerized and end-bridge structures.